Wind power is currently the most cost advantage of renewable energy. In areas with better wind energy resources, wind power costs are competitive with the cost of fuel and fuel power generation. China can use the onshore wind energy resources up to kW, ranking first in the world, but the current wind power installed capacity accounted for only 0.1% of the available wind energy resources, wind power market prospects. It is expected that in 2020 China's wind power is likely to surpass nuclear power, becoming the third largest power generation.

     Wind power is the core equipment of wind turbines, the power generated by the generator set can into the low-pressure line (commonly known as "network") when, you need to choose appropriate protection of electrical appliances, to ensure that the distribution line protection requirements.

     Selection of protective equipment

     Protection of electrical appliances mainly include circuit breakers and fuses. There are many types of circuit breakers, from the point of view of the protection of the relevant characteristics, divided into two categories of non choice and choice. In the world, the circuit breaker products and technology development is very rapid, almost every 10 years will be able to update once, continue to introduce newer and more perfect circuit breaker products. At present, the function is perfect and has the communication module of the intelligent circuit breaker, which provides the protection electrical              equipment for the power distribution line protection.

     But some of the developed countries in Europe and America, and no because of the rapid development of circuit breaker and out of the fuse, nor will fuse regarded as backward and outdated products, not only, still in the production of fuses and technology on the constant pursuit of progress  developed many new fuse products.

    Advantages and disadvantages of fuse

    Fuse has many advantages: such as good selectivity, on the lower level Fuse Fuse Rated current as long as it meets the GB and IEC standard requirements of the current selection is 1.6:1, namely superior Fuse Rated current is not less than the lower the value of 1.6 times than, for upper and lower levels can have selective cutting fault current; current limiting characteristics, high breaking capacity; relative size is small, the price is cheap. In addition, the protection of the fuse itself is very suitable for the special environment of the wind farm. Most of the wind farms are built in poor natural environment, such as Gobi, saline land or sea, dry, salt and alkali corrosion or abnormal humidity are the problems that need to be overcome. In such an environment, the internal components of the circuit breaker are easily damaged, resulting in false action or no action, and the daily maintenance cost is high. But the protection characteristic of the fuse is sealed in the quartz sand in the fuse to ensure, and the outside environment has nothing to do, can avoid the occurrence of these problems. Such as EFEN fuse products can be used in the ambient temperature is -40~50, is very suitable for the special environment of wind farm.

     However, fuse also have many shortcomings and weaknesses: fault is fused to replace the fuse; protection function of a single, only a current inverse time characteristic, overload, short circuit and ground fault to the door; a fuse, will lead to two-phase operation of undesirable outcomes.

But if used with alarm signal of the fuse, or install special micro switch auxiliary contacts in the fuse type isolating switch, you can overcome the disadvantages of the fuse, and to realize the remote monitoring. In addition, the cost of the fuse switch is cheap, and it helps to reduce the cost. Where the remote control can not be realized, the electric knife switch or switch combination can be used to compensate for the weakness of the fuse.

     Advantages and disadvantages of circuit breakers

     Non selective type circuit breaker has the advantages of fault after disconnection can be hand operated reset element does not need to be replaced, unless large short circuit current is cut off in need of repair; inverse time characteristic of long time delay release and instantaneous current release two segment protection functions, which are used for overload and short circuit protection, carry out their duties; charged operating mechanism can realize the remote control. Non selective type circuit breaker faults concentrated in the upper and lower non selective type circuit breakers are difficult to achieve selective cutting, the fault current is large, easily lead to lower level circuit breakers are instantaneous disconnection; relative price slightly high; part of the circuit breaker capacity of smaller, such as small rated current of the circuit breaker is arranged close to the location of the large capacity transformer, breaking capacity is not enough, and the existing high broken products can meet the requirements, but the price is higher.

      Selection for the main advantages and characteristics of the circuit breaker is a non selective circuit breaker of the various advantages; has multiple protection functions, such as long delay, instantaneous, short delay and ground fault protection; easy to adjust the various parameters, easy to meet the requirements of distribution lines of various protective, cascading protection function, has better selectivity. In addition, the current selection of circuit breaker products are more intelligent features, in addition to the protection function, as well as power measurement, fault recording and communication interface, etc., can achieve centralized monitoring and management of power distribution devices and systems.

     However, the choice of circuit breaker price is very high, and the size is large, especially after multiple circuit fault occurs, the protection performance will be reduced.